1. Field of the Invention
It is a primary object of my invention to provide a vehicular frame structure which provides overall a level of riding comfort, passenger and luggage capacity, comparable to the American "full size" cars of the late 1960s while remaining in a class of vehicles which has commonly come to be known as the sub-compact car. In this respect ride characteristics are tremendously enhanced over the small wheelbase sub-compact cars as are presently known today through the provision of a frame structure which allows a tremendously elongated wheelbase with respect to a narrow track which is on the order of the sub-compact cars.
According to present engineering practices, sub-compact cars maintain low weight characteristics through minimizing wheelbase and track to define an overall light weight vehicle. However, the reduction in wheelbase necessitated by available vehicular frame structures seriously detracts from the smooth ride characteristics heretofore available with full size cars having longer wheelbases. In recognition of the fact that improved ride characteristics can only be achieved through a vehicular design which affords the maximum possible wheelbase the present invention teaches a manner of maintaining an elongated wheelbase while maintaining a minimization of weight for the overall vehicle.
An object of the invention is, therefore, to provide a very light, very low, narrow and very long wheelbased automobile frame and envelope construction in which the very long wheelbase and envelope overcome the inferior ride and capacity characteristics associated with small, short wheelbased vehicles which are commonly known as in the category of sub-compact vehicles.
In order to achieve the object of a sufficiently safe, strong and rigid frame and envelope, the present invention teaches a rigid frame structure which employs as a basic load bearing member a central member which extends between the roof and the bottom of the vehicle longitudinally through the length of the structure within the front and rear wheel assembly attachments points.
In order to achieve the objects of improved riding characteristics in a vehicle having a track of the sub-compact size, the present invention teaches a tubularized body frame where tubular aluminum is arranged primarily longitudinally in the form of a truss through the center of the automobile to permit an extremely light weight spanning of the elongated wheelbase in the lightest possible manner. According to the underlying concept of this invention the sagging or bending of the body between the wheel base, inherent in any elongated wheelbase, is precluded by the novel employment of this central truss structure without prohibitive weight penalty. According to a further feature of this invention, the transverse frame includes roll bars integrally formed with side door frames to cooperate with the or central truss assembly.
The prior art approach to light weight vehicles has uniformly employed conventional frame structures or unitized body structures which rely upon either a rectangular frame or a series of interconnected welded side body panels to supply the stiffness necessary for the body section suspended between the front and rear wheel assemblies.
For conventional vehicular designs employing shortened wheelbases, such as a sub-compact category, weight minimization has involved simply structural design with frames or unitized side body panels to minimize weight while supplying sufficient resistance to a longitudinal bending moment between the wheels.
On the contrary, the present invention contemplates a vehicular design where a central truss member supplies the main longitudinal bending load bearing function so that a lightweight vehicle with an aspect ratio for wheelbase to track of between 2:1 and 3:1 is possible.
Unlike the prior art, it is a primary purpose of the instant invention to provide a vehicle having a frontal front track and overall width on the order of sub-compact vehicles and yet having a tremendously elongated length on a much longer wheelbase than presently associated with such sub-compact vehicles. As a result of the vehicular body frame and envelope construction taught herein, weight may be minimized without sacrifice of ride characteristics inherent in the short wheelbase sub-compact vehicles presently available.
2. Description of the Prior Art
The following patents illustrate various frame structures for vehicles as known to be used in the prior art:
______________________________________ France 979,994 Great Britain 728,346 Transport World, Jan. 7, 1950, Pages 21-23 FEIZER 3,827,525 HUSZAR 3,806,149 OLSON 3,759,540 BROYER 3,672,718 TAYLOR 3,616,872 EGGERT 3,292,969 WILFERT 3,290,088 HENRY 3,239,234 WILFERT 2,864,646 UHLENHAUT 2,797,954 MULLER 2,668,722 ROSE 2,507,421 FORD 2,269,451 ______________________________________
While a large number of chassis configurations are exampled by these above-noted references, there is not found any recognition of a structural approach for the specific presently disclosed desirability of achieving an elongated wheelbase by a central truss in a sub-compact vehicle.
France Pat. No. 979,994 illustrates a flat bed trailer construction with a tubular frame construction. However, unlike the instant disclosure the underframe taught by this reference is without recognition of a sub-compact chassis construction that allows for an extended wheelbase in a passenger vehicle by a central support member vertically and longitudinally extending within the passenger compartment.
Great Britain Pat. No. 728,346, and the corresponding U.S. Patent, to Uhlenhaut is an approach to a light weight chassis design by a triangular construction having external diagonal struts forming pyramidal stiffening members. In order to stiffen the body he employs a triangular construction on either side of the vehicle passenger compartment with biaces therein generating from nodal points 24 and 29. As such Uhlenhaut specifically dispenses with either roof braces or any type of centerline longitudinal members in complete distinction to the instant invention.
The Transport World article illustrates another lightweight vehicle frame approach wherein a flat horizontal underframe floor structure is relied upon for adding rigidity to a skeletal superstructure. Unlike such a conventional approach the instant invention requires no horizontal frame substructure and obtains overall longitudinal bending rigidity through a vertical and longitudinally extending frame structure that extends central within the passenger compartment.
Felzer is of interest only for his showing of a frontal frame structure. He also relies upon a total structural approach of encompassing a passenger compartment instead of employing a central main support member as in the instant invention.
The subframe approach of Huszar similarly requires a dual tubed frame on either side of the vehicle.
The chassis construction taught by Olson obtains rigidity through another form of compartmentalized horizontal floor frame, further illustrating by contrast the radical departure of the structural approach of the instant invention.
Broyer represents a lightweight and conventional wheelbase sub-compact vehicle design approach that depends upon an external configuration defined by two pyramidal frustrums. While not specific or enabling to any chassis approach, Broyer yet reflects another prior art form of reliance on external pyramidal members in contrast to the internal rigidification as taught herein.
The frame construction of Taylor includes another type of external space frame construction of tubular material to minimize weight. Similarly, the frame concept teachings of Eggert illustrates a frame construction where body panels are further used to supply rigidity to a station wagon chassis. In distinction the present invention achieves an elongated wheelbase vehicle with a relatively narrow track by relying upon an internal strut assembly extending longitudinally within the passenger space.
The patent to Wilfert is less pertinent to the state of the art of frame construction and is included to illustrate a conceptual design where rigidity is achieved through adjustment of geometrical relationships of the vehicle roof and body.
The trailer of Henry represents another common vehicle construction where a long wheelbased rigidity is desired. Henry's use of a steel channel subframe would represent a conventional approach in distinction to the inventive approach taught herein.
Wilfert illustrates a U-shaped frame concept for providing rigidity and roof support. Again, this patent is concerned with an external frame which requires at least a pair of side-by-side longitudinal members; an approach prohibitively heavy for adaptation to a vehicle with a tremendously elongated wheelbase relative to its track.
Muller and Rose each simply illustrate further frame configurations using a tubular material for minimized weight, and without further relevance to the instant invention.
Finally, the early Henry Ford patent illustrates at FIGS. 2 and 3 yet another unitized external tubular frame structure to resist twisting stresses.
While Ford also seeks as an object to isolate body panels from the structural loads on the vehicle, his approach dissimilarly relies upon an external box structure. As such any attempted elongated wheelbase development would require prohibitively heavy strengthening of both the side rails, 10, for example, in order to successfully resist the inherently increased bending loads between the axles.
In summary the prior art has not approached the creation of an elongated vehicle frame structure from an approach which purposefully relies upon a central longitudinal truss member to provide the necessary longitudinal rigidity.
Further objects, features and advantages of this invention may be appreciated with reference to the following description and drawings.